This invention relates to a seal assembly for a movable shaft which enters a housing filled with a pressurized insulating fluid and more particularly relates to a heated seal assembly for the contact actuating rod of a high voltage gas insulated interrupter of an outdoor circuit breaker in which at least one gasket seal means is provided to permit the shaft to move relative to the interrupter housing while preventing the leakage of insulating fluid from the interior of the housing.
Seal assemblies for permitting the entry of a shaft to a pressurized housing and to permit movement of the shaft relative to the housing without allowing leakage of the pressurized gas within the housing are shown, for example, in DE-OS 27,37,726 (an unexamined German Patent Application). It has been found that seals of the type disclosed in the above noted German Unexamined application may not work satisfactorily at very low temperatures which may be reached by outdoor circuit breakers exposed to Artic environmental conditions. Thus at very low temperatures conventional rubber type gasket seals can become brittle and leaky.